The present invention relates to the field of telecommunications equipment. More specifically, in one embodiment the invention provides an improved method and device for providing control, provisioning, testing, and monitoring of a subscriber loop carrier (SLC) system.
Among the best known SLC systems is one manufactured by AT&T and known as the SLC-96. The SLC-96 is a digital subscriber carrier system that provides service for up to 96 subscriber lines. Such systems use time division multiplexing techniques for transmission of signals.
FIG. 1 is an overall block diagram of the basic SLC-96 system. As shown, the system provides for the use of analog or digital central office switches 2 which transmit up to 96 analog signals to COT 4. The COT provides appropriate conversion to T1 digital format for transmission over 4 T1 lines to SLC-96 remote terminal 6, which transmits up to 96 analog telephone signals to subscriber equipment 8. The SLC-96 system is described in detail in a variety of publications including, for example, Luniewicz et al., "The SLC-96 Subscriber Loop Carrier System," AT&T Bell Laboratories Technical Journal (1984) Vol. 63, which is incorporated herein by reference in its entirety for all purposes.
While meeting with substantial success, systems such as the SLC-96 have also met with certain limitations. For example, parameter selections of the channel units (CU) on the RT are implemented under the control of conventional microswitches, dipswitches, or the like. This causes particular difficulty because resetting of many parameters requires physical removal of the board containing these switches, followed by manual resetting. This causes difficulties because of the time and labor required to perform these modifications, and the like. Such parameters which are currently implemented in this manner include, for example, transmission level changes, slope equalizer changes, impedance changes, functional type changes, and the like. Further, remote monitoring of the RT is difficult. Still further, it would be desirable to control many of these functions from a centralized remote location and to be able to obtain these improvements without complete replacement of the system.
From the above it is seen that a retrofit to provide an improved subscriber line carrier system is needed.